Line a baking sheet with aluminum foil and place a wire rack on top. Remove the bratwurst from the beer, and allow to cool to room temperature. Bake your sheet pan brats and potatoes dinner at 425 degrees for 20-25 minutes, turn the brats and stir/turn the vegetables. Healthy, crispy, and well-cooked final products make it a winner or close runner-up— and it is certainly one of the best ways to cook brats! Toss the brown sugar and cayenne pepper together in a large bowl and set aside. It is best served straight from the oven… Preheat oven to 425°. Preheat oven to 425 degrees F (220 degrees C). The oven is arguably the best way to cook any meal. Before you take the bratwurst out of the freezer or refrigerator, make sure to preheat the oven. Line a baking sheet with aluminum foil, and place a wire rack on top. How to Cook Brats in Oven. Continue to cook for an additional 20-30 minutes or until the brats are golden brown and the vegetables are roasted.